It is known to use an electrical rotary interface, also known as a slip ring, having a mercury conductor to connect two portions of an audio cable for a musical instrument that produces an electrical output, such as an electric guitar. Such a design is disclosed in U.S. Pat. No.7,473,098 to Poulos. This approach has several disadvantages. The use of a mercury-based electrical rotary interface means that the cable inherits all of the necessary handling precautions which must go along with devices containing mercury—which in particular cannot be taken aboard commercial flights. The design adopted by Poulos does not provide the requisite environmental protection for the electrical rotary interface, in terms of both resistance to tugging of the cable and impact protection. The mercury-based electrical rotary interface must be used in a vertical orientation, in order for the mercury therein to make a connection. This can be unreliable during operation leading to audio drop out and distortion.
It is therefore an object of the present invention to provide an improved audio cable for a musical instrument that produces an electrical output, in terms of both its compliance with transport regulations, durability and reliability.